1. Field of the Invention
The invention provides nucleotide sequences from Coryneform bacteria which code for the ccpA2 gene and a process for the fermentative preparation of amino acids, in particular L-lysine, by attenuation of the ccpA2 gene. The ccpA2 gene codes for the CcpA2 protein, which is the catabolite control protein A.
2. Discussion of the Background
L-Amino acids, particularly L-lysine, are used in human medicine and in the pharmaceuticals industry, in the foodstuffs industry and, most particularly, in animal nutrition.
It is known that amino acids are prepared by fermentation of strains of Coryneform bacteria, in particular Corynebacterium glutamicum. Because of their great importance, attempts are continuously being made to improve the preparation processes. Improvements to the process may concern measures relating to fermentation, for example, stirring and oxygen supply, or the composition of the nutrient media, such as the sugar concentration during the fermentation, or the working up to the product form by, for example, ion exchange chromatography, or the intrinsic output properties of the microorganism itself.
The output properties of these microorganisms are improved by employing methods of mutagenesis, selection and mutant selection. These methods yield strains that produce amino acids and are resistant to antimetabolites or are auxotrophic for metabolites important for regulation.
For a number of years, methods of recombinant DNA technology have also been used for improving the L-amino acid-producing strains of Corynebacterium. However, there remains a critical need for improved methods of producing L-amino acids and thus for the provision of strains of bacteria producing higher amounts of L-amino acids. On a commercial or industrial scale even small improvements in the yield of L-amino acids, or the efficiency of their production, are economically significant. Prior to the present invention, it was not recognized that attenuation of the ccpA2 gene encoding the catabolite control protein A (CcpA2) would improve L-amino acid yields.